I think you would have to cut less than you think. If you never saw the movie before, you probably wouldn’t even notice the difference, pacing-wise. At the very least, you might want to insert dialogue here and there to replace some of the dialogue you remove.

But any explanation that tries to fit her parents into the narrative just feels a little convoluted. I think TROS, and Rey’s story, would honestly benefit from a straight-forward conflict of dealing with the potential darkness within her, the same darkness that exists in everybody. Not just the grandchildren of Sith Lords.

At least I think it would be worth trying to edit it that way first. I genuinely think it would be less of a headache than to try and get the parent narrative to work and not feel complicated. Maybe I’m wrong though!

EDIT: Totally just my opinion though. Maybe it could work.